Undefined offset: 0 In old com_search override - PHP 8

Question

as you are all probably aware PHP is not my expertise. I'm helping plan a Joomla migration to PHP 8 (J3) and a previous developer has created a com_search override of the default_results.php file.

The 2 PHP notices I get in PHP 7.4 are:

Notice: Undefined offset: 0 in /public_html/templates/{template}/html/com_search/search/default_results.php on line 27

Notice: Trying to get property 'id' of non-object in /public_html/templates/{template}/html/com_search/search/default_results.php on line 138

The first notice refers to the return $items[0]; in the code below:

function paginateTable($tableData = null, $limit1, $limitStart1){
    if(false === is_null($tableData)){
        $items = array_chunk($tableData, $limit1);
        $posToShow = 0;
        if(sizeof($tableData) > $limit1){
            for($i = 0; $i < sizeof($items); $i++){
                $posToShow = $limitStart1/$limit1;
                
                if($limitStart1 > 0){
                    return $items[$posToShow];
                }
            }
        }
        return $items[0];
    }//end is_null($tableData)

The second notice refers to $Itemid = $menuItem->id; in the code below:

foreach($all_results as $result)
{
    if($result->catid == 18)
    {
        //$result->href = 'index.php?option=com_news&view=article&id=' . $result->id . '&Itemid=119';
        $result->href = 'index.php/news/' . $result->id . '-'.$result->alias;
        $result->description = html_entity_decode($result->description);
        $result->category = 'News';
    }elseif($result->catid == NULL){
        $result->rp_id = $result->link_id;
        $result->alias = strtolower(str_replace('\'','-', $result->title)); 
        $result->alias = str_replace(' ','-', $result->alias);
        $result->href = '/index.php/events-calendar/eventdetail/'.$result->rp_id.'/-/'.$result->alias;
        $result->description = html_entity_decode($result->description);
        $result->category = 'Events';
    }
    else{
        $link = 'index.php?option=com_content&view=article&id='.$result->id;  
        $menuItem = $menu->getItems( 'link', $link, true );
        $Itemid = $menuItem->id;
        $count_link = "index.php?option=com_content&view=article&id=" . $result->id . "&Itemid=" . $Itemid;     
        $result->href = $count_link;
        $result->description = html_entity_decode($result->description);    
        $result->category = 'Web Pages';
    }
}

I was wondering if there is a way to make this code PHP 8 compatible - there obviously may be more errors on fixing these. I'm happy to provide the entire file if needed. When switching to PHP 8 the page displays:

0 - sizeof(): Argument #1 ($value) must be of type Countable|array, null given

Which I assume is because the array returs empty. I vaguely remember something about changing from square brackets for a similar problem but I'd like a second opinion if possible.

As always, thank you for your time. It's really appreciated.

D

Edit: Updated to include link to full PHP code onlinephp.io

Answer 1

Without understanding much of the context of the task, I can advise a simpler pagination method.

My opinion is that it is almost never appropriate for an array parameter to be null. In my applications, if I am logically expecting a variable to contain iterable data, I do not allow any scalar or null values.

My snippet assumes that your starting integer is zero-based (not one-based). I am building in a protection from negative starts and negative lengths using abs() because array_slice()'s behaviour with negative values may not be what you want. (If you understand the consequences of negative integers with this function and actually desire the behaviour, then the abs() calls can be removed.

Code: (Demo)

function paginateTable(array $data = [], int $limit = 10, int $start = 0): array
{
    return array_slice($data, abs($start), abs($limit));
}

---

As for the problem with $menu->getItems( 'link', $link, true );, according the Joomla documentation, you can most directly call something like:

$menuItem = $menu->getItem($result->id);

...if I am understanding the context/data.

Answer 2

for your first notice, array_chunk either returns an array or false, but your return statement always assumes that it's going to be an array. To fix this immediate issue, I would replace your return statement with a ternary check:

return $items && isset($items[0]) ? $items[0] : null;

This way, it checks that the zero indexed array item exists before returning it, otherwise it returns null. You'll need to check that returning null doesn't cause an issue in whichever function is calling it. It may be that returning false may be the required option but I'd need to see the code to work that out.

For your second notice, the problem is that $menu->getItems looks to be assuming that the result is going to be a single menu object, but getItems should be returning an array of those objects. If you look at this info section it shows you how you need to loop through the result of getItems to access the menu objects your code is expecting - https://docs.joomla.org/Menu_and_Menuitems_API_Guide#Properties_and_Parameters

Hope that gets you moving in the right direction but post back if you're still stuck.